The role of eye muscle motoneurons and reticular formation burst units will be studied in monkey microsaccades. The effects of vestibulocerebellectomy in the cat will be studied on adaptation of the vestibuloocular reflex to reversing prisms and on the remission of spotaneous nystagmus due to vestibular lesions. Hypometric saccades produced by lesions of the vermis in the monkey will be analyzed. The location of field potentials and single units in the cat pons antidromically activated by mlf stimulation will be determined. Optokinetic nystagmus and circular vection will be studied in patients with cerebellar lesions.